module example
   implicit none
   private
   public :: dp, test_routine, &
             test_function, test_type, str_function
   integer, parameter :: dp = selected_real_kind(15, 307)
   type test_type
      real(kind=dp) :: r = 1.0d-3
      integer :: i
   end type test_type

contains

   subroutine test_routine( &
      r, i, j, k, l)
      integer, intent(in)                                :: r, i, j, k
      integer, intent(out)                               :: l

      l = test_function(r, i, j, k)
   end &
      subroutine

   pure function test_function(r, i, j, &
                               k) &
      result(l)
      integer, intent(in)                                :: r, i, j, k
      integer                                            :: l

      l = r + i + j + k
   end function
   function &
      str_function(a) result(l)
      character(len=*)                                   :: a
      integer                                            :: l

      if (len(a) < 5) then
         l = 0
      else
         l = 1
      end if
   end function

end module

program example_prog
   use example, only: dp, test_routine, test_function, test_type, str_function

   implicit none
   integer :: r, i, j, k, l, my_integer, m
   integer, dimension(5) :: arr
   integer, dimension(20) :: big_arr
   integer :: endif
   type(test_type) :: t
   real(kind=dp) :: r1, r2, r3, r4, r5, r6
   integer, pointer :: point

   point => null()

! 1) white space formatting !
!***************************!
! example 1.1
   r = 1; i = -2; j = 3; k = 4; l = 5
   r2 = 0.0_dp; r3 = 1.0_dp; r4 = 2.0_dp; r5 = 3.0_dp; r6 = 4.0_dp
   r1 = -(r2**i*(r3 + r5*(-r4) - r6)) - 2.e+2
   if (r .eq. 2 .and. r <= 5) i = 3
   write (*, *) (merge(3, 1, i <= 2))
   write (*, *) test_function(r, i, j, k)
   t%r = 4.0_dp
   t%i = str_function("t  % i   =  ")

! example 1.2
   my_integer = 2
   i = 3
   j = 5

   big_arr = [1, 2, 3, 4, 5, &
              6, 7, 8, 9, 10, &
              11, 12, 13, 14, 15, &
              16, 17, 18, 19, 20]

! example 1.3: disabling auto-formatter:
   my_integer = 2 !&
   i          = 3 !&
   j          = 5 !&

!&<
   my_integer = 2
   i          = 3
   j          = 5
!&>

   big_arr = [ 1,  2,  3,  4,  5, & !&
               6,  7,  8,  9, 10, & !&
              11, 12, 13, 14, 15, & !&
              16, 17, 18, 19, 20] !&

! example 1.4:

   big_arr = [1, 2, 3, 4, 5,&
           &  6, 7, 8, 9, 10, &
           & 11, 12, 13, 14, 15,&
            &16, 17, 18, 19, 20]

! 2) auto indentation for loops !
!*******************************!

! example 2.1
   l = 0
   do r = 1, 10
      select case (r)
      case (1)
         do_label: do i = 1, 100
            if (i <= 2) then
               m = 0
               do while (m < 4)
                  m = m + 1
                  do k = 1, 3
                     if (k == 1) l = l + 1
                  end do
               end do
            end if
         end do do_label
      case (2)
         l = i + j + k
      end select
   end do

! example 2.2
   do m = 1, 2
      do r = 1, 3
         write (*, *) r
         do k = 1, 4
         do l = 1, 3
         do i = 4, 5
            do my_integer = 1, 1
            do j = 1, 2
               write (*, *) test_function(m, r, k, l) + i
            end do
            end do
         end do
         end do
         end do
      end do
   end do

! 3) auto alignment for linebreaks   !
!************************************!

! example 3.1
   l = test_function(1, 2, test_function(1, 2, 3, 4), 4) + 3*(2 + 1)

   l = test_function(1, 2, test_function(1, 2, 3, 4), 4) + &
       3*(2 + 1)

   l = test_function(1, 2, &
                     test_function(1, 2, 3, 4), 4) + &
       3*(2 + 1)

   l = test_function(1, 2, &
                     test_function(1, 2, 3, &
                                   4), 4) + &
       3*(2 + 1)

! example 3.2
   arr = [1, (/3, 4, 5/), 6] + [1, 2, 3, 4, 5]

   arr = [1, (/3, 4, 5/), &
          6] + [1, 2, 3, 4, 5]

   arr = [1, (/3, 4, 5/), &
          6] + &
         [1, 2, 3, 4, 5]

   arr = [1, (/3, 4, &
               5/), &
          6] + &
         [1, 2, 3, 4, 5]

! example 3.3
   l = test_function(1, 2, &
                     3, 4)

   l = test_function( &
       1, 2, 3, 4)

   arr = [1, 2, &
          3, 4, 5]
   arr = [ &
         1, 2, 3, 4, 5]

! 4) more complex formatting and tricky test cases !
!**************************************************!

! example 4.1
   l = 0
   do r = 1, 10
      select case (r)
      case (1)
         do i = 1, 100; if (i <= 2) then! comment
               do j = 1, 5
                  do k = 1, 3
                     l = l + 1
! unindented comment
                     ! indented comment
                  end do; end do
            elseif (.not. j == 4) then
               my_integer = 4
            else
               write (*, *) " hello"
            end if
         end do
      case (2)
         l = i + j + k
      end select
   end do

! example 4.2
   if ( &
      l == &
      111) &
      then
      do k = 1, 2
         if (k == 1) &
            l = test_function(1, &
                              test_function(r=4, i=5, &
                                            j=6, k=test_function(1, 2*(3*(1 + 1)), str_function(")a!(b['(;=dfe"), &
                                                                 9) + &
                                            test_function(1, 2, 3, 4)), 9, 10) &
                ! test_function(1,2,3,4)),9,10) &
                ! +13*str_function('') + str_function('"')
                + 13*str_function('') + str_function('"')
      end & ! comment
         ! comment
         do
   end if

! example 4.3
   arr = [1, (/3, 4, &
               5/), &
          6] + &
         [1, 2, 3, 4, 5]; arr = [1, 2, &
 3, 4, 5]

! example 4.4
   endif = 3
   if (endif == 2) then
      endif = 5
   else if (endif == 3) then
      write (*, *) endif
   end if

! example 4.5
   do i = 1, 2; if (.true.) then
         write (*, *) "hello"
      end if; end do

end program
